Knowledge Base

Why does flow-control sometimes not engage properly on a Dell™ PowerConnect™ 3024 or 5012 switch?

Turn off the High-Priority Traffic Optimization option. The High-Priority Traffic Optimization should only be enabled in scenarios where the default switch settings result in a unacceptably high latency for high-priority traffic.

When the High-Priority Traffic Optimization option is enabled, flow-control is not engaging for ports that are receiving packets with normal priority.

With High-Priority Traffic Optimization, an advanced priority-based head-of-line blocking prevention algorithm is being used. This algorithm will drop normal priority packets in the ingress queue if they cannot be sent to the egress queue of the destination port, due to over-subscription. This internal dropping of normal priority packets ensures that no high-priority packets are being held-up in the switch. Due to the internal dropping of packets, flow control will not engage on the ingress port for normal priority packets.

NOTE: This does not affect ports that receive high-priority packets.

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